I recently spent two nights at the Sheraton on the park and I think it's one of the nicer business hotels in Sydney. My preference is usually boutique hotels, which this hotel is not, but there are character elements which make this hotel one to consider.
The lobby and reception area has a real buzz to it. It's plush, and has an overall quality feel to it. Staff are friendly and approachable and present themselves well. The room I stayed in was on the 18 floor with a great view of Hyde Park. The room itself is one of the largest rooms I have ever stayed in. The bathroom was lovely and well equiped, the bed comfortable and the pillow selection good. The gym and pool area are also great. Having recently stayed at the Westin Sydney where the pool was very undesirable, I'd say the Sheraton's gym and pool area are first class.
Don't hesitate in booking this hotel.